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authorPavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>2019-07-25 11:44:26 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2019-08-20 17:26:21 +0200
commitdcb1578069dd072f9aec74e3024cadb9ed0f3aae (patch)
treea3046cc620d45f20e983df481651c27402579767
parent978ae0e99c1760c228eef2d320386daab3bf5b10 (diff)
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util/qemu-timer: refactor deadline calculation for external timers
icount-based record/replay uses qemu_clock_deadline_ns_all to measure the period until vCPU may be interrupted. This function takes in account the virtual timers, because they belong to the virtual devices that may generate interrupt request or affect the virtual machine state. However, there are a subset of virtual timers, that are marked with 'external' flag. These do not change the virtual machine state and only based on virtual clock. Calculating the deadling using the external timers breaks the determinism, because they do not belong to the replayed part of the virtual machine. This patch fixes the deadline calculation for this case by adding new parameter for skipping the external timers when it is needed. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> -- v2 changes: - added new parameter for timer attribute mask Message-Id: <156404426682.18669.17014100602930969222.stgit@pasha-Precision-3630-Tower> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--cpus.c17
-rw-r--r--include/qemu/timer.h8
-rw-r--r--qtest.c3
-rw-r--r--tests/ptimer-test-stubs.c4
-rw-r--r--tests/ptimer-test.c6
-rw-r--r--util/qemu-timer.c30
6 files changed, 53 insertions, 15 deletions
diff --git a/cpus.c b/cpus.c
index f4ad855..85cd451 100644
--- a/cpus.c
+++ b/cpus.c
@@ -556,7 +556,8 @@ void qtest_clock_warp(int64_t dest)
assert(qtest_enabled());
aio_context = qemu_get_aio_context();
while (clock < dest) {
- int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
int64_t warp = qemu_soonest_timeout(dest - clock, deadline);
seqlock_write_lock(&timers_state.vm_clock_seqlock,
@@ -616,7 +617,8 @@ void qemu_start_warp_timer(void)
/* We want to use the earliest deadline from ALL vm_clocks */
clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ ~QEMU_TIMER_ATTR_EXTERNAL);
if (deadline < 0) {
static bool notified;
if (!icount_sleep && !notified) {
@@ -1352,7 +1354,12 @@ static int64_t tcg_get_icount_limit(void)
int64_t deadline;
if (replay_mode != REPLAY_MODE_PLAY) {
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ /*
+ * Include all the timers, because they may need an attention.
+ * Too long CPU execution may create unnecessary delay in UI.
+ */
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
/* Maintain prior (possibly buggy) behaviour where if no deadline
* was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
@@ -1373,8 +1380,8 @@ static void handle_icount_deadline(void)
{
assert(qemu_in_vcpu_thread());
if (use_icount) {
- int64_t deadline =
- qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
if (deadline == 0) {
/* Wake up other AioContexts. */
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 5bcab93..85bc6eb 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -62,13 +62,15 @@ typedef enum {
* The following attributes are available:
*
* QEMU_TIMER_ATTR_EXTERNAL: drives external subsystem
+ * QEMU_TIMER_ATTR_ALL: mask for all existing attributes
*
* Timers with this attribute do not recorded in rr mode, therefore it could be
* used for the subsystems that operate outside the guest core. Applicable only
* with virtual clock type.
*/
-#define QEMU_TIMER_ATTR_EXTERNAL BIT(0)
+#define QEMU_TIMER_ATTR_EXTERNAL ((int)BIT(0))
+#define QEMU_TIMER_ATTR_ALL 0xffffffff
typedef struct QEMUTimerList QEMUTimerList;
@@ -177,6 +179,8 @@ bool qemu_clock_use_for_deadline(QEMUClockType type);
/**
* qemu_clock_deadline_ns_all:
* @type: the clock type
+ * @attr_mask: mask for the timer attributes that are included
+ * in deadline calculation
*
* Calculate the deadline across all timer lists associated
* with a clock (as opposed to just the default one)
@@ -184,7 +188,7 @@ bool qemu_clock_use_for_deadline(QEMUClockType type);
*
* Returns: time until expiry in nanoseconds or -1
*/
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type);
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask);
/**
* qemu_clock_get_main_loop_timerlist:
diff --git a/qtest.c b/qtest.c
index 59df1b6..d8b4857 100644
--- a/qtest.c
+++ b/qtest.c
@@ -654,7 +654,8 @@ static void qtest_process_command(CharBackend *chr, gchar **words)
int ret = qemu_strtoi64(words[1], NULL, 0, &ns);
g_assert(ret == 0);
} else {
- ns = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ ns = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
}
qtest_clock_warp(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns);
qtest_send_prefix(chr);
diff --git a/tests/ptimer-test-stubs.c b/tests/ptimer-test-stubs.c
index 54b3fd2..ed393d9 100644
--- a/tests/ptimer-test-stubs.c
+++ b/tests/ptimer-test-stubs.c
@@ -88,9 +88,9 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
return ptimer_test_time_ns;
}
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask)
{
- QEMUTimerList *timer_list = main_loop_tlg.tl[type];
+ QEMUTimerList *timer_list = main_loop_tlg.tl[QEMU_CLOCK_VIRTUAL];
QEMUTimer *t = timer_list->active_timers.next;
int64_t deadline = -1;
diff --git a/tests/ptimer-test.c b/tests/ptimer-test.c
index b30aad0..5b20e91 100644
--- a/tests/ptimer-test.c
+++ b/tests/ptimer-test.c
@@ -50,13 +50,15 @@ static void ptimer_test_set_qemu_time_ns(int64_t ns)
static void qemu_clock_step(uint64_t ns)
{
- int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
int64_t advanced_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns;
while (deadline != -1 && deadline <= advanced_time) {
ptimer_test_set_qemu_time_ns(deadline);
ptimer_test_expire_qemu_timers(deadline, QEMU_CLOCK_VIRTUAL);
- deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+ QEMU_TIMER_ATTR_ALL);
}
ptimer_test_set_qemu_time_ns(advanced_time);
diff --git a/util/qemu-timer.c b/util/qemu-timer.c
index 37ecfe3..d428fec 100644
--- a/util/qemu-timer.c
+++ b/util/qemu-timer.c
@@ -247,14 +247,38 @@ int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
* ignore whether or not the clock should be used in deadline
* calculations.
*/
-int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
+int64_t qemu_clock_deadline_ns_all(QEMUClockType type, int attr_mask)
{
int64_t deadline = -1;
+ int64_t delta;
+ int64_t expire_time;
+ QEMUTimer *ts;
QEMUTimerList *timer_list;
QEMUClock *clock = qemu_clock_ptr(type);
+
+ if (!clock->enabled) {
+ return -1;
+ }
+
QLIST_FOREACH(timer_list, &clock->timerlists, list) {
- deadline = qemu_soonest_timeout(deadline,
- timerlist_deadline_ns(timer_list));
+ qemu_mutex_lock(&timer_list->active_timers_lock);
+ ts = timer_list->active_timers;
+ /* Skip all external timers */
+ while (ts && (ts->attributes & ~attr_mask)) {
+ ts = ts->next;
+ }
+ if (!ts) {
+ qemu_mutex_unlock(&timer_list->active_timers_lock);
+ continue;
+ }
+ expire_time = ts->expire_time;
+ qemu_mutex_unlock(&timer_list->active_timers_lock);
+
+ delta = expire_time - qemu_clock_get_ns(type);
+ if (delta <= 0) {
+ delta = 0;
+ }
+ deadline = qemu_soonest_timeout(deadline, delta);
}
return deadline;
}